Diffraction of transmission light through triangular apertures in array of retro-reflective microprisms

Area of Science:

• Optics and Photonics
• Materials Science

Background:

• Microprism arrays are crucial for retroreflective sheeting.
• Understanding their optical performance requires detailed modeling.
• Fabrication imperfections can significantly impact diffraction patterns.

Purpose of the Study:

• To model microprism arrays as multiperiod blazed gratings.
• To interpret the origins of observed hexagram diffraction patterns.
• To analyze the relationship between fabrication defects and optical performance.

Main Methods:

• Modeling microprisms as triangular aperture blazed gratings.
• Applying multiple-beam interference and diffraction array theorems.
• Analyzing diffraction patterns from manufactured retroreflective sheeting samples.

Main Results:

• A model successfully described microprism arrays and explained hexagram diffraction patterns.
• Zonal and line ghost fringes were correlated with structural imperfections.
• Geometrical performance, including dihedral angles, was evaluated through diffraction measurements.

Conclusions:

• The blazed grating model accurately represents microprism arrays.
• Fabrication quality directly influences the optical fidelity of diffraction patterns.
• Diffraction pattern analysis is a viable method for assessing microprism geometrical performance.